1. Field of the Invention
This invention relates to a method of vertical welding of aluminum and aluminum alloys, and more particularly to an improvement in the method of vertical welding of aluminum and aluminum alloys while oscillating in a welding groove an electrode in a closed pattern corresponding substantially to the groove shape.
2. Description of the Prior Art
In the method of vertical welding of aluminum and aluminum alloys, a deltaic (triangular) oscillating pattern is usually adopted, for example, for V-groove welding. There has been proposed a method in which a vertical butt joint of large aluminum structures of a relatively large thickness is welded by oscillating an electrode along the deltaic pattern according to MIG welding performing the vertical ascending welding effectively with a reduced number of layers, as disclosed, for example, in Petrochemical Engineering, 5, 9, pp. 73-79 (1973). In such a conventional welding method, however, since the welding is conducted by applying a certain prescribed welding current throughout oblique sides (portions corresponding to groove faces) of the deltaic pattern and the bottom side (the portion corresponding to the open side of the groove), because of the high thermal conductivity of the material to be welded, especially in the case of aluminum alloys, insufficient weld penetration results caused.